Interaction of bovine uterine luminal protein with interleukin-2 and the interleukin-2 receptor of T lymphocytes.
Bovine uterine luminal proteins (ULP) collected on Day 17 of pregnancy were tested for inhibition of binding of interleukin-2 (IL-2) to the IL-2 receptor (IL-2R) of bovine (CLC) and human (HLC) T lymphocytes and for binding to IL-2. Additional experiments assessed IL-2 binding to the p55 alpha chain (Tac protein) of the IL-2R of HLC. High- and low-molecular weight (Mr) ULP components (H-ULP greater than 248,000 Mr and L-ULP 21,000 Mr, respectively) inhibited (p less than 0.05 and 0.01, respectively) the binding of 125I-IL-2 to the IL-2R of CLC, whereas only H-ULP inhibited (p less than 0.05) binding to the IL-2R (presumably, the p75 beta chain) of HLC. H-ULP failed (p greater than 0.05) to bind to the p55 alpha chain of the IL-2R of HLC. For IL-2 binding, L-ULP failed (p greater than 0.05) to bind 125I-IL-2 in short (2 h)-term and long (45 h)-term experiments, whereas binding was evident (p less than 0.05) for H-ULP at 2 h of incubation. For H-ULP, mean (+/- SEM) percentages for bound and unbound 125I-IL-2 were 70.1 +/- 11.4 and 29.9 +/- 11.4, respectively. Further purification of H-ULP yielded a component (1.76 x 10(6) Mr) that bound 11.7% of 125I-IL-2 and inhibited (p less than 0.01) thymidine uptake and binding of 125I-IL-2 to the IL-2R of CLC. H-ULP-mediated suppression of lymphocyte proliferation may result from blocking IL-2R recognition of IL-2 as well as binding to IL-2, whereas suppression by L-ULP may predominantly result from blocking IL-2R.
Segerson
E C
EC
Department of Animal Science, North Carolina A&T State University, Greensboro 27411.
Libby
D W
DW
D000818:Animals; D002417:Cattle; D002455:Cell Division; D002850:Chromatography, Gel; D004347:Drug Interactions; D005260:Female; D006023:Glycoproteins; D006801:Humans; D007376:Interleukin-2 / Q000032:analysis / Q000494:pharmacology*; D011506:Proteins / Q000032:analysis / Q000494:pharmacology*; D011869:Radioligand Assay; D015375:Receptors, Interleukin-2 / Q000032:analysis / Q000378:metabolism*; D015843:Serpins; D013601:T-Lymphocytes / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*
D006023:Glycoproteins; D007376:Interleukin-2; D011506:Proteins; D015375:Receptors, Interleukin-2; D015843:Serpins; C029708:uterine luminal fluid proteins